Guard ring technologies, e.g., segmented guard rings, are used in many different semiconductor technologies such as GaAs, SiGe, RFCMOS, and RFSOI. For example, radio frequency (RF) circuits require segmented guard rings to avoid parasitic coupling and inductive coupling (the latter phenomenon which can occur with continuous guard rings).
RF technologies typically comprise non-porous dielectric material at the middle of the line (MOL) and back end of the line (BEOL) processes. To make further improvements to RF technologies, e.g., improvements in RF circuitry performance, low-k dielectric, porous material at the MOL or BEOL processing levels is required. The low-k dielectric, porous material, e.g., SiCOH or p-SiCOH, is widely used in advanced CMOS technologies such as 90 nm and smaller generations for several BEOL wiring levels.
Particularly useful in these low-k dielectric, porous applications is a guard ring to prevent moisture ingress which can cause SiCOH cracking or degraded copper reliability (e.g., electromigration, stress migration, etc.). But the use of a segmented guard ring can cause reliability fails in these low-k dielectric, porous applications. Accordingly, RFSOI chips with segmented guard ring and low-K SiCOH or p-SiCOH MOL/BEOL are known to be incompatible.